What is the permissible extent of a stop and frisk?

In general, police may not detain a suspect any longer than is necessary to effectuate the purpose of the stop, and the police may only use the least intrusive measures possible to verify or dispel the officer’s suspicions. In other words, a stop and frisk (or Terry stop) must be confined in scope to an intrusion reasonably designed to discover guns, knives, clubs, or other hidden instruments which could be used to assault the police officer.